Process for the production of mixtures of alkali phthalocyanines and metalfree phthalocyanine



r' 3,050,189 l Patented Oct. 23, 1962 l 2 3,060,189 ever, at IOU-150 C., particularly in the presence of sol- PROCESS FOR THE PRODUCTION OF MIXTURES vents' ALKALI PHTHALGCYANINES AND L. It was not to have been foreseen that the relatively FREE PHTHALOCYANINE weakly active alkali sulphides used as reducing agents at Emil Stocker and Andr Pugin, Riehen, near Basel, Switzthe relatively low reaction temperatures of about 100- f g assignol's Geigy -y Basel, SWiiZeT- 150 C. would lead to this favourable result and here, an apparently, have a specific action. The use of the stable g p l 3 1 53 alkali sulphides is both cheaper and more simple as well am l f i W} zer an as less dangerous than the use of alkali metals or amides arms. (6.. 260-3145) which are sensltive to oxygen and water and whlch re- The present invention concerns a process for the proquire particular technical apparatus. Thus, the process duction of a mixture of alkali phthalocyanines and metalaccording to the invention is also a substantial technical free phthalocyanine. advance.

It is known that mixtures of alkali phthalocyanines Technically, the mixture of alkali phthalocyanine/ and metal-free phthalocyanine can be produced by rephthalocyanine is produced according to the invention by acting phthalonitrile with alkali metals in alcohols. A heating a mixture of phthalonitrile and alkali sulphide to variation of this process consists in adding small amounts about the melting point of the phthalonitrile at which of sulphur or of sodium sulphide to the reaction mass bepoint the strongly exothermic reaction begins. To counfore the alkali metal is added. This reaction proceeds teract the heat, advantageously an inorganic salt which formally according to the empiric equations: is inert under the reaction conditions, such as e.g. sodium anon wherein A represents an alkali metal and R represents an sulphate or sodium chloride, possibly together with smallalkyl radical, e.g. the ethyl radical. The known producer amounts of inert organic compounds such as e.g. urea, tion process from phthalonitrile and alkali amides is also the sodium salt of xylene sulphonic acid, diethylene glyto be interpreted in the same way. col monoethyl ether or pentaerythrite, is added to the It is important in the reaction that two electrons are reaction mixture at the beginning. taken up by 4 molecules of phthalonitrile. The process Preferably, however, the alkali sulphide and the thus depends on electron transference, i.e. it is dependent phthalonitrile are dissolved in an organic solvent, mainly on reducing agent. in an ether alcohol, particularly methoxyethanol or eth-v Whether, in the reaction system of the alkali metal/ oxyethanol, or in a thioether alcohol such as e.g. 2,2- phthalonitrile/ alcohol, it is the alkali metal itself or the dihydroxydiethyl thioether. It is also possible to disatomic hydrogen formed as intermediary from the metal solve them in any proportions in a mixture of such an and the alcohol which acts as reducing agent is not imalcohol and an inert organic solvent, e.g. in a possibly mediately Obvious f the question as to electron halogenated aromatic hydrocarbon such as xylene or 1,2- donor, is not important. It is known that both alkali dichlorobenzene. Also, formamide isa suitable solvent.

m ta alkali amides and atomic hy g are the most During dissolution, the temperature rises quickly, the soactive reducing agents. They easily split off an electron. lu-tion turns blue and the alkali phthalocyanine/phthalo- It is thus comprehensible that the processes mentioned cyanine mixtu i f ed whi h an b nverted in th proceed more easily and produce better yields than those k w manner i to metal-free phthalocyanine. The Which use l S active reducing agents- Therefore, by minimal amount of alkali sulphides so used is 0.5 mol the known production processes, in which phthalonitrile 0 to 4 mol of phthalonitrila If the amount of alkali is reacted with an alkali alcoholate as reducing agent in phide is raised to 055 to 0.6 me], then the yield alsoim the solution of the alcohol used for the alcoholate, mixcreases A higher content of alkali sulphides, for exam tures of alkali phthalocyanines and metal-free phthalo- P16 1 mol does not cause any further increase in the cyanine are obtained in yields which hardly exceed 50% M f 1k h of the theoretical. Also other reducing agents such as we 0 a al p thalocyamnc/PhthaloCyanme mlxture mercaptans alkan 013mm es acid amides or hydroquinones it only increases the content of alkali phthalocyanme 1n the mixture.

WhlCh have been suggested for the production of phthalo- A cyanine from phthalonitrile, only give poor yields. mg t 15 mventlon, compounqs of i It has now been found that mixtures of alkali phthaloformula A2Sn are emplfJyed a1ka11 sulphldes; m

cyanines and metal-free phthalocyanines are obtained in a which fqmula A alkah metal partlcular sodllrfl pure form and good yields which even exceed those obalso 1t can be hthlum or PtaSS111m, fl11d IS 3 P tajned b h process using 1k 1i metal d l h l or tive whole number from one to seven inclusive, preferusing alkali amide, if phthalonitrile is reacted with anab1Y0I1e,tW0,thr6e0r 0 rhydrous alkali sulphides in the absence of alkali metals Particularly good results are attained with Na s to at temperatures of IOU-300 C., advantageously how- Na S as well as mixtures of these sulphides, whereas I with hot water.

3 higher sulphides are less suitable because of their tendency to split elementary sulphur.

The following examples illustrate the invention. In the examples, when the term sodium sulphide is employed Na s is intended. Where not otherwise stated, parts are given therein as parts by weight. The temperatures are in degrees centigrade. The relationship of parts by weight to parts by volume is as that of kilogrammes to litres.

Example I 33.8 parts of 69% sodium sulphide dried in vacuo at 160 and finely pulverised are added to a suspension of 256 parts of 100% phthalonitrile in 360 parts of glycol monoethyl ether while stirring well. The suspension first becomes yellow, then green and finally blue and the temperature rises of its own accord to about 80". When the temperature drops, external heating is applied to 130 and this temperature is kept for 3 hours.

To hydrolyse the sodium phthalocyanine formed, 500 parts of water and 100 parts of 30% caustic soda lye are added and the mixture is heated for 2 hours at 100 while stirring well. The suspension is filtered hot and the residue is washed with hot dilute caustic soda lye and then After drying, 216 parts of pure metalfi'ee phthalocyanine are obtained.

Example 2 12 parts of sodium hydroxide and 14.4 parts of sulphur are dissolved at 100 in 200 parts of glycol monomethyl ether. 128 parts of 100% phthalonitrile are added at 50 to the solution of sodium tetrasulphide formed and the mixture is heated for 2 hours at 123 whereupon it becomes blue and more viscous.

To hydrolyse the sodium phthalocyanine formed, 250 parts of water and 50 parts of 30% caustic soda lye are added to the suspension and the mixture is heated for 2 hours at 100". After filtering, washing the residue with dilute caustic soda lye and hot water and drying, 103 parts of metal-free phthalocyanine are isolated. It is somewhat less pure than that obtained according to Example 1.

If in this example, instead of 12 parts of sodium hydroxide, equivalent amounts of lithium hydroxide or potassium hydroxide are used, then the metal-free phthalocyanine is obtained in similarly good yields.

Example 3 205 parts of 100% phthalonitrile and 23 parts of 69% sodium sulphide which has been dried in vacuo at 160 and finely pulverised, are added to 200 parts of o-dichlorobenzene and 20 parts of glycol monoethyl ether and the whole is heated for 3 hours at 150. The o-dichlorobenzene is then removed from the deep blue suspension by steam in the presence of 150 parts of 30% caustic soda lye. After filtering off, washing with hot water and drying, 180 parts of pure metal-free phthalocyanine are obtained.

Example 4 51.2 parts of 100% phthalonitrile and 7.8 parts of 69% sodium sulphide are heated in 75 parts of formamide for 2% hours at 120-125". A very thick paste is formed which afterwards is diluted with water, boiled and filtered. To further purify, the sodium phthaloc yanine obtained as filter residue is extracted with hot dilute caustic soda lye. After filtering ofi, washing and drying, 38 parts of metalfree phthalocyanine are isolated.

In this example, if instead of formamide, 100 parts of thiodiglycol are used, then 32 parts of metal-free phthalocyanine are obtained.

Example 5 108.4 parts of 100% phthalonitrile and 10 parts of 69% finely pulverised sodium sulphide are heated in 300 parts of glycol monoethyl ether for 2 hours at 130. The suspension is filtered hot and the residue washed with glycol monoethyl ether and water. After drying, 90 par-ts of sodium phthalocyanine are isolated. To hydrolyse, this is heated in 400 parts of methyl alcohol for 5 hours under reflux. After filtering off, washing with hot water and drying, 84 parts of metalfree phthalocyanine are obtained.

Example 6 102.4 parts of 100% phthalonitrile, 200 parts of anhydrous sodium sulphate and 45 parts of 69% anhydrous sodium sulphide are mixed and then ground into a finely granular powder. This powder is put into an oven previously heated to 200 and baked for 20 minutes. An exothermic reaction occurs and the temperature of the mixture rises to 234. It is then finely pulverised in a mill and extracted with hot dilute caustic soda lye and afterwards with hydrochloric acid in the presence of Turkey red oil. In this way 60 parts of metal-free phthalocyanine of good purity are isolated.

The yield of metal-free phthalocyanine can be increased to 70 to parts if in this example, 40 parts of the sodium salt of xylene sulphonic acid or 40 parts of pentaerythrite or 20 parts of diethyleneglycol monoethyl ether are added to the phthalonitrile.

What we claim is:

1. Process for the production of mixtures of alkali phthalocyanines and metal-free phthalocyanine comprising reacting phthalonitrile with anhydrous alkali sulphides of the formula A 8 wherein A is an alkali metal and n is a positive whole numberof from 1 to 4 inclusive, at a temperature between and 300 C.

2. Process according to claim 1 wherein the alkali sulphide is Na S.

3. Process according to claim 1. wherein the reaction is carried out in an organic solvent.

4. Process according to claim 3 wherein the organic liquid is glycol monoalkyl ether and the alkali sulphide is Nags.

5. Process according to claim 3 wherein the organic liquid is a mixture of 0-dichlorobenzene and glycol monoalkyl ether and the alkali sulphide is Na S.

6. Process according to claim 1 wherein the reaction is carired out in the presence of an inorganic salt.

7. Process according to claim 6 wherein the inorganic salt is anhydrous sodium sulphate and the alkali sulphide is Na S.

Heilbron et a1 July 19, 1938 Wettstein Jan. 11, 1955 

1. PROCESS FOR THE PRODUCTION OF MIXTURES OF ALKALI PHATHALOCYANINES AND MATEL-FREE PHALOCYANINE COMPRISING REACTING PHTHALONITRILE WITH ANHYDROUS ALKALI SULPHIDES OF THE FORMULA A2SN WHEREIN A IS AN ALKALI METAL AND N IS A POSITIVE WHOLE NUMBER OF FROM 1 TO 4 INCLUCIVE, AT A TEMPERATURE BETWEEN 100 AND 300* C. 